Tele phone-receiver



(No Model.)

wfo. TURNBULL.

TELEPHONE RECEIVER. No. 344,333. Patented June 22, 1886.

rams.

\VILLIAM C. TURNBULL, OF BALTIMORE, MARYLAND.

TELEPHONE-RECEIVER.

SPECIFICATION forming part of Letters Patent No. 344,333, dated June 22, 1886.

Application filed February Q6, 1886. Serial No. 193,318. (No model.)

To all whom it may concern.-

Be it known that I, \VILLIAM O. TURNBULL, of Baltimore. in the State of Maryland, have invented an Improved Telcphone-Receiver, of which the following is a specification.

The object of my invention is to produce a telephone-receiver which will clearly and distinctly reproduce transmitted speech or signals with improved effect.

In the accompanying drawings, Figure l is a view,- partly in section, with the casing removed, of so much of the instrumentas is necessary to illustrate my invention; and Fig. 2 is a similar view.

A represents a barmagnet, which is to be arranged in the handle of the case of the instrument. On the end of this magnet is secured at soft-iron or magnetic pole-piece, B, having upright ends on which ordinary cores and electric bobbins are mounted, the ends being suiiieiently far apart to permit of the arrangement between the cores of a drum, 0, carrying two magnetic vibrating drum-heads, plates, or disks, (1, upon which the cores respectively act. The drum 0 may be formed of a metal rim, 0, in the outer edges of which .the vibrating plates or disks (1 are respect ively mounted in any suitable way. This drum may be formed with a solid center of hard rubber, vulcanized fiber, wood, or other suitable material, 0, which is slightly narrower than the surrounding metallic band 0, so as to leave vocalizing-chambers between the inner faces of the disks or plates and the sides of the block. The entire drum may be secured in place by a scre\v,f, which screws into thehandle-magnet A and into the solid core or filling e of the drum, as clearly shown in Fig. 1.

In this form of instrument the core a is cut away on each side, as shown at a, so as to form sound-passages which lead from the V0- calizirig-chamber on each side of the drum to a sound-aperture, a, in the periphery of the drum, which is to be arranged opposite the opening in the casin The instrument shown in Fig. 2 is of substantially similar construction, except that instead of making the drum with a core or iilling the drum may be hollow, a post, 0, being provided therein for the re ccption of the screw which fastens the drum to the handlemagnet.

I am aware of the patent of \Vaite, No. 298,924, and the patent of Gray, No. 204,029, and I make no claim to the construction shown therein.

I claim as my invention 1. The combination of a magnet, A, apolcpiece secured thereon having two upright portions, a core and bobbin on each end thereof, a drum arranged between said cores, and :1 vibrating plate on each face of the drum in suitable proximity to one of said cores.

2. The combination ofa hollow drum formed of a rim, 0, of metal or other suitable material, a vibrating plate which forms each side thereof, and a coil and core arranged in suitable proximity to eaclrvibrating plate, but not in contact therewith.

In testimony whereof I have hereunto subscribed my name.

VILLIAM G. TURNBULL.

\Vitnesses:

Geo. DIOOAFFRAY, E. O. DAVIDSON. 

